1. Field of the Invention
The invention relates to a fluid pump system for an engine in an automotive vehicle, and more particularly, to a dual fluid pump system wherein each pump is driven by a respective shaft of a dual balance shaft system in the engine.
2. Description of the Prior Art
Automotive vehicles typically include a fluid pump assembly for circulating and delivering oil to the moving components of an engine. It is well known in the art to drive the fluid or oil pump assembly with a crankshaft from the engine.
An engine may also include a dual balance shaft assembly for reducing engine vibration and noise due to reciprocating pistons and rods in the engine. The engine crankshaft typically drives the dual balance shaft assembly. The dual balance shafts are driven in opposite directions by the crankshaft to offset each other's inertial moments and offset vibrations due to the reciprocal motion of the pistons and rods. However, it is common for the dual balance shaft assembly to cause vibration and noise within the engine. It is known to drive an oil pump assembly with a shaft from a balancing shaft assembly of the engine, rather than using the crankshaft for minimizing vibration and noise due to the rotation the dual balance shafts. Typically, the dual balance shaft assembly is enclosed between first and second halves of a balance shaft housing and the oil pump assembly is enclosed between first and second halves of an oil pump housing. The balance shaft and oil pump housings are fixedly secured to each other by bolts.
It remains desirable to provide an oil pump assembly that reduces vibration and noise due to the dual balance shaft assembly, while providing increased oil pump efficiency over conventional oil pump designs. Further, it remains desirable to provide a simplified, cost effective dual balance shaft and oil pump assembly that uses fewer components than conventional dual balance shaft and oil pump assembly designs.